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Home & garden.

Updated: 28 Feb 2022

How to install and test carbon monoxide detectors

Fitting your carbon monoxide detector correctly is as important as buying the right one in the first place. Read on for our expert tips.
Matt Stevens
CO on wall1

The more fuel-burning appliances you have in your home, the more carbon monoxide detectors you need.

If you only have one fuel-burning appliance, such as a gas boiler in the kitchen, you’ll only need one carbon monoxide detector.

But if you have other appliances, such as a gas fire, log burner or even a fuel burning Aga range cooker, you’ll need to fit a carbon monoxide detector in each room that these appear in.

Read on for tips for how to install a carbon monoxide detector - and then check our list of the best carbon monoxide alarms that have passed our stringent safety tests.

How to install your carbon monoxide detector

Setting up and installing your carbon monoxide alarm is a straightforward DIY task and can be as easy as resting it on a high shelf in a room with a fuel-burning appliance. 

Always read and follow the manufacturer’s instructions on siting, testing, servicing and replacing the alarm. Pay particular attention to the unit’s battery life and when it will need replacing. Most alarms will last between five and seven years, with some lasting for as long as 10 years.

But be on your guard if the instructions say you should not install the alarm in your kitchen. We’ve found that cheap imported alarms that have failed our lab tests all offer unsafe advice about not installing the detectors in the kitchen, where in UK homes you are likely to find a gas boiler or cooker.

You can see which alarms have failed our tests on our Don't Buy carbon monoxide detectors page.

Where to install your carbon monoxide detector

Fit your alarm high-up in the same room as the potential source of carbon monoxide, around 15cm from the ceiling and at least one metre away from boilers, cookers and fires. But make sure it’s not directly above a source of heat or steam. It doesn't need to be fixed to a wall, and a shelf is often suitable.

How to test a carbon monoxide detector

Test your alarm regularly using the test button, and replace the batteries annually or when the low battery signal sounds. Sealed battery alarms have a battery that will last as long as the alarm and won’t need to be replaced.